Designated as "Linthicum Heights" and zip code 21090 by the US Postal Service, Linthicum has been traditionally divided into two distinct communities each with its own community association and identity. These two communities, split by the Baltimore Beltway in 1957, are Linthicum and North Linthicum (or, alternatively, Linthicum-Shipley and North Linthicum.) Both communities developed as a result of their locations adjacent to the Baltimore and Annapolis Short Line railroad which brought commuters to the original truck farming community.

As a developed community, Linthicum began with the 1908 founding of the "Linthicum Heights Company", though a "Linthicum" or "Linthicum's" station on the 1887 Annapolis and Baltimore Short Line railroad existed at least as early as 1889. The community's name was from the area's primary land-owning family since an 1801 purchase by Abner Linthicum.[2]

The BWI Business District West Nursery area is located in Linthicum along the West Nursery Road corridor. The business district is home to numerous companies, offices, and commercial services.

Two major highways run through the CDP. The Baltimore Beltway (Interstate 695) runs northwest-southeast through Linthicum and intersects with the Baltimore–Washington Parkway (Maryland Route 295), which runs northeast-southwest. By the parkway it is 6 miles (10 km) northeast to downtown Baltimore and 32 miles (51 km) southwest to Washington, D.C.

According to the United States Census Bureau, the CDP has a total area of 5.5 square miles (14.3 km2), of which 5.4 square miles (14.1 km2) is land and 0.039 square miles (0.1 km2), or 0.81%, is water.[1]

There were 2,877 households out of which 28.3% had children under the age of 18 living with them, 64.3% were married couples living together, 8.7% had a female householder with no husband present, and 23.3% were non-families. 19.5% of all households were made up of individuals and 10.5% had someone living alone who was 65 years of age or older. The average household size was 2.61 and the average family size was 2.98.

In the CDP, the population was spread out with 21.3% under the age of 18, 6.2% from 18 to 24, 25.5% from 25 to 44, 26.4% from 45 to 64, and 20.6% who were 65 years of age or older. The median age was 43 years. For every 100 females there were 93.0 males. For every 100 females age 18 and over, there were 91.7 males.

The median income for a household in the CDP was $61,479, and the median income for a family was $72,821. Males had a median income of $46,586 versus $35,104 for females. The per capita income for the CDP was $27,559. About 2.0% of families and 3.6% of the population were below the poverty line, including 3.1% of those under age 18 and 7.8% of those age 65 or over.

The community of North Linthicum is defined by the North Linthicum Improvement Association as the area bounded by the Patapsco River from the Baltimore Beltway (I-695) to Old Annapolis Road (MD 648), Old Annapolis Road from the Patapsco River to the Baltimore Beltway, the Baltimore Beltway from Old Annapolis Road to the Baltimore–Washington Parkway, the Baltimore–Washington Parkway from the Baltimore Beltway to Hammonds Ferry Road, and Hammonds Ferry Road from the Baltimore–Washington Parkway to the Patapsco River.